This invention relates to a combined air conditioning (heating/cooling) and hot water service system or unit in which hot or cold water from a heat pump type chiller unit is employed not only for heating or cooling the room but also for servicing of hot water.
A certain type of such combined system or unit makes use of a hot water servicing heat exchanger in the refrigerant system of the heat pump type chiller unit in order to service hot water simultaneously with the heating or cooling the room. Such a system gives rise to a complicated refrigerant cycle and an increase in the number of brazing points thus frequently causing gas leakage in the refrigerant cycle. In addition, it is necessary to provide separate heat exchangers for heating, cooling and servicing of hot water in the refrigerant cycle of the heat pump type chiller unit. The result is an increased volume of the refrigerant charged into the system and generation of excess refrigerant depending on prevailing operational conditions thus frequently causing troubles due to such excess refrigerant such as liquid-back into the compressor. Moreover, when the room heating and servicing of hot water are effected simultaneously, the heating capacity may fluctuate with prevailing hot water service needs thus interfering with satisfactory room heating. Meanwhile, on most occasions, the heating or cooling operation is not continued all day long and hence there is a time zone the heat pump type chiller unit is not in operation in the manner known per se.